Characterization of the novel duplicated PRLR gene at the late-feathering K locus in Lohmann chickens

Abstract

A partial duplication of the prolactin (PRL) receptor gene (designated asdPRLR) has been identified at the late-feathering (LF)Klocus on chromosome Z of some chicken strains recently, implying thatdPRLRis probably a candidate gene associated with LF development in chickens. However, little is known about the structure, functionality, and spatiotemporal expression of thedPRLRgene in chickens. In this study, using 3′-RACE and RT-PCR, the full-length cDNA of thedPRLRobtained from the kidneys of male Lohmann layer chickens carrying aKallele was cloned. The cloneddPRLRis predicted to encode a membrane-spanning receptor of 683 amino acids, which is nearly identical to the original PRLR, except for its lack of a 149-amino acid C-terminal tail. Using a 5× STAT5–Luciferase reporter system and western blot analysis, we demonstrated that dPRLR expressed in HepG2 cells could be potently activated by chicken PRL and functionally coupled to the intracellular STAT5 signaling pathway, suggesting that dPRLR may function as a novel receptor for PRL. RT-PCR assays revealed that similar to the originalPRLRgene,dPRLRmRNA is widely expressed in all embryonic and adult tissues examined including the skin of male Lohmann chickens with aKallele. These findings, together with the expression ofPRLmRNA detected in the skin of embryos at embryonic day 20 and 1-week-old chicks, suggest that skin-expressed dPRLR and PRLR, together with plasma and skin-derived PRL, may be involved in the control of the LF development of chicks at hatching. Moreover, the wide tissue expression ofdPRLRimplies that dPRLR may regulate other physiological processes of chickens carrying theKallele.